Suddenly, the government of the United States has discovered the virtues of international law. It may be waging an illegal war against a sovereign state; it may be seeking to destroy every treaty which impedes its attempts to run the world, but when five of its captured soldiers were paraded in front of the Iraqi television cameras on Sunday, Donald Rumsfeld, the US defence secretary, immediately complained that "it is against the Geneva convention to show photographs of prisoners of war in a manner that is humiliating for them".

He is, of course, quite right. Article 13 of the third convention, concerning the treatment of prisoners, insists that they "must at all times be protected... against insults and public curiosity". This may number among the less heinous of the possible infringements of the laws of war, but the conventions, ratified by Iraq in 1956, are non-negotiable. If you break them, you should expect to be prosecuted for war crimes.

This being so, Rumsfeld had better watch his back. For this enthusiastic convert to the cause of legal warfare is, as head of the defence department, responsible for a series of crimes sufficient, were he ever to be tried, to put him away for the rest of his natural life.

His prison camp in Guantanamo Bay, in Cuba, where 641 men (nine of whom are British citizens) are held, breaches no fewer than 15 articles of the third convention. The US government broke the first of these (article 13) as soon as the prisoners arrived, by displaying them, just as the Iraqis have done, on television. In this case, however, they were not encouraged to address the cameras. They were kneeling on the ground, hands tied behind their backs, wearing blacked-out goggles and earphones. In breach of article 18, they had been stripped of their own clothes and deprived of their possessions. They were then interned in a penitentiary (against article 22), where they were denied proper mess facilities (26), canteens (28), religious premises (34), opportunities for physical exercise (38), access to the text of the convention (41), freedom to write to their families (70 and 71) and parcels of food and books (72).

They were not "released and repatriated without delay after the cessation of active hostilities" (118), because, the US authorities say, their interrogation might, one day, reveal interesting information about al-Qaida. Article 17 rules that captives are obliged to give only their name, rank, number and date of birth. No "coercion may be inflicted on prisoners of war to secure from them information of any kind whatever". In the hope of breaking them, however, the authorities have confined them to solitary cells and subjected them to what is now known as "torture lite": sleep deprivation and constant exposure to bright light. Unsurprisingly, several of the prisoners have sought to kill themselves, by smashing their heads against the walls or trying to slash their wrists with plastic cutlery.

The US government claims that these men are not subject to the Geneva conventions, as they are not "prisoners of war", but "unlawful combatants". The same claim could be made, with rather more justice, by the Iraqis holding the US soldiers who illegally invaded their country. But this redefinition is itself a breach of article 4 of the third convention, under which people detained as suspected members of a militia (the Taliban) or a volunteer corps (al-Qaida) must be regarded as prisoners of war.

Even if there is doubt about how such people should be classified, article 5 insists that they "shall enjoy the protection of the present convention until such time as their status has been determined by a competent tribunal". But when, earlier this month, lawyers representing 16 of them demanded a court hearing, the US court of appeals ruled that as Guantanamo Bay is not sovereign US territory, the men have no constitutional rights. Many of these prisoners appear to have been working in Afghanistan as teachers, engineers or aid workers. If the US government either tried or released them, its embarrassing lack of evidence would be brought to light.

You would hesitate to describe these prisoners as lucky, unless you knew what had happened to some of the other men captured by the Americans and their allies in Afghanistan. On November 21 2001, around 8,000 Taliban soldiers and Pashtun civilians surrendered at Konduz to the Northern Alliance commander, General Abdul Rashid Dostum. Many of them have never been seen again.

As Jamie Doran's film Afghan Massacre: Convoy of Death records, some hundreds, possibly thousands, of them were loaded into container lorries at Qala-i-Zeini, near the town of Mazar-i-Sharif, on November 26 and 27. The doors were sealed and the lorries were left to stand in the sun for several days. At length, they departed for Sheberghan prison, 80 miles away. The prisoners, many of whom were dying of thirst and asphyxiation, started banging on the sides of the trucks. Dostum's men stopped the convoy and machine-gunned the containers. When they arrived at Sheberghan, most of the captives were dead.

The US special forces running the prison watched the bodies being unloaded. They instructed Dostum's men to "get rid of them before satellite pictures can be taken". Doran interviewed a Northern Alliance soldier guarding the prison. "I was a witness when an American soldier broke one prisoner's neck. The Americans did whatever they wanted. We had no power to stop them." Another soldier alleged: "They took the prisoners outside and beat them up, and then returned them to the prison. But sometimes they were never returned, and they disappeared."

Many of the survivors were loaded back in the containers with the corpses, then driven to a place in the desert called Dasht-i-Leili. In the presence of up to 40 US special forces, the living and the dead were dumped into ditches. Anyone who moved was shot. The German newspaper Die Zeit investigated the claims and concluded that: "No one doubted that the Americans had taken part. Even at higher levels there are no doubts on this issue." The US group Physicians for Human Rights visited the places identified by Doran's witnesses and found they "all... contained human remains consistent with their designation as possible grave sites".

It should not be necessary to point out that hospitality of this kind also contravenes the third Geneva convention, which prohibits "violence to life and person, in particular murder of all kinds, mutilation, cruel treatment and torture", as well as extra-judicial execution. Donald Rumsfeld's department, assisted by a pliant media, has done all it can to suppress Jamie Doran's film, while General Dostum has begun to assassinate his witnesses.

It is not hard, therefore, to see why the US government fought first to prevent the establishment of the international criminal court, and then to ensure that its own citizens are not subject to its jurisdiction. The five soldiers dragged in front of the cameras yesterday should thank their lucky stars that they are prisoners not of the American forces fighting for civilisation, but of the "barbaric and inhuman" Iraqis.